Basic Chemistry Concepts for Anatomy & Physiology

Basic Chemistry Concepts for Anatomy & Physiology

Define Matter, Element, and Atom

Understanding the fundamental building blocks of matter is essential for studying anatomy and physiology, as all biological structures and processes are based on chemical principles.

• Matter: Anything that has mass and occupies space.

• Element: A pure substance made of only one kind of atom; cannot be broken down by chemical means.

• Atom: The smallest unit of an element that retains its chemical properties.

Three States of Matter & Human Body Examples

Matter exists in different physical states, each with distinct properties. The human body contains all three states:

• Solid: Has definite shape and volume. Example: Bones

• Liquid: Has definite volume but takes the shape of its container. Example: Blood plasma

• Gas: No definite shape or volume. Example: Oxygen in lungs

Four Elements Making Up 96.1% of Body Mass

The majority of the human body's mass is composed of four key elements:

Element	Atomic Symbol
Oxygen	O
Carbon	C
Hydrogen	H
Nitrogen	N

Example: These elements are found in water, proteins, nucleic acids, and other biomolecules.

Subatomic Particles in an Atom

Atoms are composed of three main subatomic particles, each with specific properties and locations:

Particle	Charge	Location
Proton	+1	Nucleus
Neutron	0	Nucleus
Electron	−1	Orbitals around nucleus

Additional info: The number of protons determines the atomic number and identity of the element.

Define Molecule, Element vs. Compound

Atoms can combine in various ways to form molecules and compounds, which are essential for biological structure and function.

• Molecule: Two or more atoms bonded together.

• Element: A substance made of only one type of atom (e.g., O2).

• Compound: A substance made of two or more different elements chemically bonded (e.g., H2O).

Example: Water (H2O) is a compound; oxygen gas (O2) is a molecule and an element.

Types of Chemical Bonds

Chemical bonds hold atoms together in molecules and compounds. The type of bond affects the properties of the substance.

• Ionic Bond: Transfer of electrons between atoms (e.g., NaCl).

• Covalent Bond: Sharing of electrons between atoms (e.g., H2O).

• Hydrogen Bond: Weak attraction between a hydrogen atom and an electronegative atom (e.g., between water molecules).

Polar vs. Nonpolar Covalent Bonds:

Type	Description	Example
Polar	Unequal sharing of electrons	H2O
Nonpolar	Equal sharing of electrons	O2

Define Cation and Anion

Ions are charged particles formed when atoms gain or lose electrons:

• Cation: Positively charged ion (lost electrons).

• Anion: Negatively charged ion (gained electrons).

Example: Na+ is a cation; Cl− is an anion.

Types of Chemical Reactions

Chemical reactions are essential for metabolism and other physiological processes. The main types include:

• Synthesis (Anabolic): Building complex molecules. Equation: $A + B \rightarrow AB$

• Decomposition (Catabolic): Breaking down molecules. Equation: $AB \rightarrow A + B$

• Exchange: Parts of molecules are swapped. Equation: $AB + CD \rightarrow AD + CB$

Example: Protein synthesis (anabolic); digestion of food (catabolic).

Factors Affecting Reaction Rate

The speed of chemical reactions in the body is influenced by several factors:

• Temperature

• Concentration of reactants

• Particle size

• Catalysts (e.g., enzymes)

Additional info: Enzymes are biological catalysts that increase reaction rates without being consumed.

Metabolism

Metabolism refers to all chemical reactions in the body that maintain life, including both anabolic (building) and catabolic (breaking down) processes.

• Anabolic reactions: Synthesize complex molecules from simpler ones.

• Catabolic reactions: Break down complex molecules into simpler ones, releasing energy.

Example: Cellular respiration is a catabolic process; protein synthesis is anabolic.